Draft: Composer 2.8.1 downgrade 2.8.0

Closes #3479446

.gitlab-ci/pipeline.yml

@@ -100,6 +100,7 @@ variables:
 
 .run-tests: &run-tests
   script:
+    - composer self-update 2.8.0
     # Need to pass this along directly.
     - sudo MINK_DRIVER_ARGS_WEBDRIVER="$MINK_DRIVER_ARGS_WEBDRIVER" -u www-data php ./core/scripts/run-tests.sh --color --keep-results --types "$TESTSUITE" --concurrency "$CONCURRENCY" --repeat "1" --sqlite "./sites/default/files/tests.sqlite" --dburl $SIMPLETEST_DB --url $SIMPLETEST_BASE_URL --verbose --non-html --all --ci-parallel-node-index $CI_PARALLEL_NODE_INDEX --ci-parallel-node-total $CI_PARALLEL_NODE_TOTAL